ClickHouse/docs/en/operations/system-tables/text_log.md

system.text_log

Contains logging entries. The logging level which goes to this table can be limited to the text_log.level server setting.

Columns:

• event_date (Date) — Date of the entry.
• event_time (DateTime) — Time of the entry.
• event_time_microseconds (DateTime) — Time of the entry with microseconds precision.
• microseconds (UInt32) — Microseconds of the entry.
• thread_name (String) — Name of the thread from which the logging was done.
• thread_id (UInt64) — OS thread ID.
• level (Enum8) — Entry level. Possible values:
  • 1 or 'Fatal'.
  • 2 or 'Critical'.
  • 3 or 'Error'.
  • 4 or 'Warning'.
  • 5 or 'Notice'.
  • 6 or 'Information'.
  • 7 or 'Debug'.
  • 8 or 'Trace'.
• query_id (String) — ID of the query.
• logger_name (LowCardinality(String)) — Name of the logger (i.e. DDLWorker).
• message (String) — The message itself.
• revision (UInt32) — ClickHouse revision.
• source_file (LowCardinality(String)) — Source file from which the logging was done.
• source_line (UInt64) — Source line from which the logging was done.

Example

SELECT * FROM system.text_log LIMIT 1 \G

Row 1:
──────
event_date:              2020-09-10
event_time:              2020-09-10 11:23:07
event_time_microseconds: 2020-09-10 11:23:07.871397
microseconds:            871397
thread_name:             clickhouse-serv
thread_id:               564917
level:                   Information
query_id:                
logger_name:             DNSCacheUpdater
message:                 Update period 15 seconds
revision:                54440
source_file:             /ClickHouse/src/Interpreters/DNSCacheUpdater.cpp; void DB::DNSCacheUpdater::start()
source_line:             45

Original article